The amount of cloud space you get should equal the amount of space on the iOS devices you bought.
If I buy a 64GB iPad, I should be able to back it up to the cloud.
...not that I'd want to do it all at once, but still...
the backups are only the metadata and app data if the app supports it
last time i restored my wife's iphone via icloud/wifi it installed the apps from the app store. its not like it backs up the app